A projection display system is a system which can project an image or a video onto a projector screen, and can be connected with a computer, a video compact disc (VCD), a digital versatile disc (DVD), a Blu-ray disc (BD), a game console, a digital video (DV) and the like via various interfaces to play corresponding video signals. With the rapid development of display technology, the touch screen projection displaying system has become a research hotspot of great concern. The touch screen projection displaying system can switch pictures without a control terminal, and is widely used in the fields of multimedia education, cartoons and games, traffic and transportation, finance, news media, governmental conferences and the like.
In the prior art there is a touch screen projection displaying system, which comprises a rear projection screen, an infrared touch frame, a projector set and a control device, wherein the rear projection screen comprises a projector screen and a light sensitive assembly disposed at the projector screen, the light sensitive assembly detects the luminance of the projector screen, and generates a corresponding sensed signal; the infrared touch frame senses a touch action, and generates a corresponding electrical signal; the projector set projects a plurality of images onto the projector screen, and enables the edges of adjacent images to be coincident; the control device acquires the coincident areas of the images on the projector screen according to the sensed signal, controls the projector set to homogenize the luminance at various points of the projector screen according to the coincident areas, and merges the plurality of images into a gapless integral picture, and in the meantime acquires the touch coordinates of the electrical signal generation position according to the electrical signal, and controls the projector set to switch pictures according to the touch coordinates.
The above touch screen projection displaying system adopts infrared touch, which has the problems of a small number of touch points, generally not greater than 10 points, and of a low touch sensing precision, thus having poor touch effect.